High Availability storage (HA storage) is a storage system that is continuously operational. Redundancy is a key feature of HA storage, as it allows data to be kept in more than one place and protects it.

OpenEBS Jiva Volume is a controller with one or more replicas. The controller is an iSCSI target whereas the replica plays the role of disk. The controller exposes the iSCSI target while the actual data is written. The controller and each individual replica run inside a dedicated container.

OpenEBS Jiva Volume controller exists as a single instance but there can be multiple instances of OpenEBS Jiva volume replicas. Persistent data is synchronized between replicas.

OpenEBS Jiva Volume HA is based on various scenarios as explained in the following sections.

OpenEBS Jiva Volume with two or more replicas and a single controller¶

NOTE: In this deployment, each of the replicas get scheduled in a unique K8s node, that is, a K8s node will never have two replicas of an OpenEBS volume.

Scenario 1 - When an OpenEBS volume controller POD crashes, the following occurs.